News & Views

Tension – Torsion Machine for Extra Loading Modes

By Bill Mohr on Thursday, October 28th, 2010

tension torsion

I just recently designed an experiment where the combination of pieces of sheet steel and the service loading were very difficult to model with loading from our servo-hydraulic tension and compression test machines. But we had another machine type that allowed an easier fixturing approach. We have a tension – torsion machine that can load each mode either alone or simultaneously. It this case the best option was loading using just the torsion direction to induce a bending moment across the welded joint area. All we needed was the fixtures from both sides of the sheet construction to set this up. This is an intermediate step between the approach of building a large fixture to test the entire component and testing one weld and then extrapolating to the entire component. This intermediate approach can be used far more often than it is now and provide much additional information. Fatigue lifetime tests tend to need approaches like this, since they can be dominated by geometrical parameters that are not included in the “one weld” testing approach

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